If you are working on something cool, let mp3Car mods know. They select a forum member each month for a grant of up to $100 in hardware or software or other products. (Products do not have to be available on the mp3Car Store.)
If you don't have ideas for a grant, check out the Carputer Wishlist to see if there is something that you can do to help the hobby and apply for a grant to get started.

Discussion for creating OS hardware, using Arduinos, etc. in the car.
Open source hardware is where the creators have decided to completely publish all the source, schematics, firmware, software, bill of materials, parts list, drawings and "board" files to recreate the hardware - and any use is allowed including commercial.